Communication systems, such as satellite communication systems, typically include a modem (also often called an indoor unit “IDU”) which communicates with a transceiver (also known as an outdoor unit “ODU”) over a cable. Generally, the modem receives signals from a computer and transmits those signals to the ODU over a transmit cable. The ODU sends and receives signals to and from a satellite. The ODU communicates signals received from the satellite to the IDU over a receive cable. The IDU is further configured to control the ODU. For example, the IDU may be configured to control the level of the RF (radio frequency) signal to be transmitted to a satellite.
Collectively, the IDU, ODU, and cable are generally termed “ground station”. The ground station may be located on, for example, a stationary structure (e.g., building) or a moving structure (e.g., vehicle) such that communication with the satellite is permissible. In many applications, the IDU is located near or within a computer, e.g., a card that fits inside the computer processor or a box in proximity to the computer. One or more cables interconnect the IDU with the ODU. The ODU may be located outside, e.g., on the roof of a building or a vehicle. Another ground station, provides similar functionality for the opposite end of the communication link in order to connect the ground station to a telecommunications or computer network.
Typically, the signals communicated between the modem and the transceiver are communicated as intermediate frequency (IF) signals. In addition to IF signals, the cable or cables between the IDU and ODU often convey power and control signals from the IDU to the ODU.
Moreover, the cable or cables may be configured to provide telemetry functionality, i.e., remote measurement and reporting of information of interest. Various methods of providing telemetry have been used to convey information from the ODU to the IDU. However, these methods typically involve adding separate cables to carry the telemetry information, or involve complicated and relatively expensive modulator/demodulator technology. Thus, it is desirable to have improved methods of communicating telemetry type information, and the like, between the ODU and IDU.